Exploratory preliminary study to examine genetic polymorphisms of CYP2A6 nicotine metabolism in women cigarette smokers. CYP2A6 has been shown recently to be the major form of P450 in the biotransformation of nicotine to cotinine and cotinine to 3'-hydoxy cotinine. Compared to Caucasian women, African American women smokers have significantly higher plasma cotinine levels while smoking fewer cigarettes per day. One possible explanation for higher plasma levels is that African Americans may be ultra rapid biotransformers of nicotine to cotinine.